The present invention relates to a travelator, moving ramp or escalator.
Travelators, moving ramps or escalators wherein people are transported on a conveyor horizontally or at an upward/downward angle are disclosed for example in International Patent Application Publication No. WO 02/26612 and U.S. Pat. No. 5,117,960. Such a travelator or escalator comprises a people mover and a balustrade extending alongside the people mover throughout its length. The balustrade comprises a handrail belt implemented as an endless loop. The passenger can grasp the upper handhold portion of the handrail belt for support. The lower return portion is hidden from view, running inside the frame structure of the travelator or escalator. The balustrade further comprises a balustrade frame, which comprises a turn-around guide placed at the end of the balustrade to form a so-called turn-around and to support and guide the turn-around portion of the handrail belt so as to allow the direction of motion of the handrail belt to be turned through 180°.
As explained in U.S. Pat. No. 5,477,954 and U.S. Pat. No. 5,634,546, the turn-around guide forming the turn-around usually comprises a number of spaced apart pressure rollers arranged in a sequence in the form of an arc of about 180°.
Referring again to International Patent Application Publication No. WO 02/26612 and U.S. Pat. No. 5,117,960, the handrail belt is driven by a drive assembly comprising a drive belt formed as an endless loop. The drive belt is in driving contact with the handrail belt over a predetermined length, which in this description is called contact portion. The drive belt is driven by a power means.
International Patent Application Publication No. WO 02/26612 discloses a system in which a drive belt functions as the drive element of both the people mover and the handrail belt. The drive belt is in contact with the visible outer side of the handrail belt within its straight return portion, and pressure rollers are provided on the opposite inner side of the handrail belt. As the driving force of the drive belt acts on the visible outer side of the handrail belt, WO 02/26612 discloses that the handrail belt should be made of a durable material to prevent damage. The problem is that a handrail belt manufactured from special materials is expensive. Moreover, the current type of driving solution used to drive the handrail belt is not applicable for use in travelators, moving ramps or escalators in which the frame is intended to have as low a construction height as possible and which are designed to be mounted on a fixed base without a pit formed in the fixed base.
U.S. Pat. No. 5,117,960 discloses an arrangement for driving the handrail belt by a drive belt engaging the return portion of the handrail belt directly. The handrail belt is driven as it is passing through a nip formed by the two belts. The contact portion of the drive belt is in contact with the inner side of the handrail belt, i.e. with the bottom of the groove in the belt. The drive belt is pressed against the handrail belt by a plurality of springloaded pressure rollers. On the opposite side of the handrail belt is a second, freely running pressure belt which is passed over deflection and pressure rollers and implemented as an endless loop which contacts the visible outer side of the handrail belt. A problem with this solution is that the handrail belt is subject to pressing forces that may cause fatigue of the belt material in the course of time. The pressure belt contacting the visible outer side of the handrail belt causes wear of the handrail belt. In addition, in order to achieve a sufficient driving force, the pressure belt and its deflection and pressure rollers are necessarily needed, which leads to a massive and expensive construction.